Subaru 2004 LEGACY Service Manual page 174

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
9 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Disconnect the connector from the elec-
tronic throttle control.
4) Measure the resistance between ECM con-
nector and electronic throttle control connector.
Connector & terminal
(B136) No. 18 — (E57) No. 6:
(B136) No. 29 — (E57) No. 4:
(B136) No. 16 — (E57) No. 5:
10 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
Measure the resistance between ECM connec-
tor and chassis ground.
Connector & terminal
(B136) No. 16 — Chassis ground:
(B136) No. 18 — Chassis ground:
(B136) No. 29 — Chassis ground:
11 CHECK SENSOR POWER SUPPLY.
1) Connect the ECM connector.
2) Turn the ignition switch to ON.
3) Measure the voltage between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 5 (+) — Engine ground (
12 CHECK SHORT CIRCUIT IN ECM.
1) Turn the ignition switch to OFF.
2) Measure the resistance between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 6 — Engine ground:
(E57) No. 4 — Engine ground:
13 CHECK SENSOR OUTPUT.
1) Connect all the connectors.
2) Turn the ignition switch to ON.
3) Read the data of main throttle sensor signal
using Subaru Select Monitor.
14 CHECK SENSOR OUTPUT.
Read the data of sub throttle sensor signal
using Subaru Select Monitor.
15 CHECK POOR CONTACT.
Check the poor contact in connector between
ECM and electronic throttle control.
16 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Disconnect the connector from the elec-
tronic throttle control.
4) Measure the resistance between ECM con-
nector and electronic throttle control connector.
Connector & terminal
(B136) No. 35 — (E57) No. 3:
(B136) No. 18 — (E57) No. 6:
(B136) No. 29 — (E57) No. 4:
Check
Is the resistance less than 1
Ω?
Is the resistance more than 1
MΩ?
Is the voltage 4.5 — 5.5 V?
−
):
Is the resistance more than 10
Ω?
Is the voltage 4.63 V?
Is the voltage 4.73 V?
Is there poor contact?
Is the resistance less than 1
Ω?
EN(H6DO)(diag)-243
ENGINE (DIAGNOSTICS)
Yes
Go to step 10. Repair the open
circuit of harness
connector.
Go to step 11. Repair the ground
short circuit of har-
ness.
Go to step 12. Repair the poor
contact in ECM
connector.
Replace the ECM
if defective. <Ref.
to FU(H6DO)-34,
Engine Control
Module (ECM).>
Go to step 13. Repair the poor
contact in ECM
connector.
Replace the ECM
if defective. <Ref.
to FU(H6DO)-34,
Engine Control
Module (ECM).>
Go to step 14. Go to step 16.
Go to step 15. Go to step 16.
Repair the poor Go to step 21.
contact.
Go to step 17. Repair the open
circuit of harness
connector.
No